ABSORPTIONS OF $NH_{3}, CO_{2}, H_{2}O, N_{2}O$, and $CH_{4}$ AS INFRARED CALIBRATION STANDARDS: COMPARISON OF ABSOLUTE ACCURACIES

Author Institution: Jet Propulsion Laboratory, California Institute of TechnologyAn absorption spectrum containing the above species has been recorded during an 8 hour period at $0.006 cm^{-1}$ resolution in the region from $550 cm^{-1}$ to $5000 cm^{-1}$ using a Fourier transform spectrometer at Kitt Peak National Observatory. The line positions from this single scan have been compared to values in the literature in order to confirm the absolute accuracies of available standards. The gas sample conditions and references used are as follows:[Figure] Species Path Pressure Region References Accuracies (m) (Torr) (m) $(10^{6} cm^{-1}) NH_{3} 193 0.001 11.0 1)$ Poynter et al., Mol. Phys. $51, 393 (1984) 100 CO_{2} 193 1.03 11.0 2)$ Freed et al., IEEE QA-16, $1195 (1980) 2 H_{2}O 10 .01+ 6.0 3)$ Guelachvili, J. Opt. Soc. Am. 73, 137 (1983) 50 $N_{2}O 2.4 3.5 9.0 4)$ Guelachvili, Canad. J. Phys. 60, 1334 (1982) 50 2.2 5) Pollock et al. (in preparation) $100 CH_{4} 2.4 0.03 3.3 6$) Knight et al., IEEE IM-29, 257 (1980) 0.1 Detailed comparisons reveal that the laser standards ($CO_{2}, CH_{4}$ and $N_{2}O$) and the $NH_{3}$ parameters to be consistent within the accuracies of the present data $(\pm 0.0001 cm^{-1})$ but that the values of Refs. 3 and 4 are systematically high by 0.0002 to $0.0004 cm^{-1}$, values larger than the stated accuracies